Grading Checklist: Multicast Traffic Not Crossing Router

• Verified that ip multicast-routing is enabled globally on the router
• Checked for PIM configuration on each VLAN interface
• Identified that PIM is NOT configured on router interfaces as the root cause
• Explained that without PIM, the router does not build multicast routing entries
• Checked IGMP group memberships on router interfaces
• Reviewed show ip mroute output and noted empty or missing entries
• Proposed fix: enable PIM on all interfaces participating in multicast
• Addressed RP configuration if PIM sparse mode is appropriate
• Mentioned IGMP snooping and querier considerations on the switches
• Checked that multicast TTL from the source application is greater than 1
• Verified the fix with show ip mroute and traffic arriving at receivers
• Discussed the difference between PIM sparse and dense modes and when to use each